DELF: Safeguarding deletion correctness in Online Social Networks. - Katriel Cohn-Gordon; Georgios Damaskinos; Divino Neto; Joshi Cordova; Benoît Reitz; Benjamin Strahs; Daniel Obenshain; Paul Pearce; Ioannis Papagiannis; Available Media (USENIX Security Symposium, 2020)